## ------------------case that not match the rules to use topk---------------------------## #without order by select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 limit 5; #without limit select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by avg(c1); #without group by select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 order by avg(c1) limit 5; #is select for update select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by avg(c1) limit 5 for update nowait; #without topk hint select avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by avg(c1) limit 5; #with found_rows select /*+topk(20 6)*/ sql_calc_found_rows avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by avg(c1) limit 5; #with subquery select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by (select c1 from t1_topk where c2 = 1) limit 5; #with distinct select /*+topk(20 6)*/ distinct avg(c1), avg(c2), avg(c3) from t1_topk where c2 <10 group by c2 order by avg(c1) limit 5; #with group_concat will not use topk select /*+topk(20 6)*/ sum(c1), avg(c2), group_concat(c3, c1) from t1_topk where c2 <10 group by c2 order by avg(c1) limit 5; #not based table select /*+topk(20 6)*/ avg(c1), avg(c2), avg(c3) from (select * from t1_topk where c2 <10) as a group by a.c2 order by avg(a.c1) limit 5; # join table select /*+topk(20 6)*/ distinct avg(t1_topk.c1), avg(t1_topk.c2), avg(t1_topk.c3) from t1_topk , t2_topk group by t1_topk.c2 order by avg(t1_topk.c1) limit 5; ##-----------------case that match rules of topk-----------------------## ##hash agg + topk_sort select /*+topk(1 2) use_hash_aggregation*/ c3, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by c3 limit 1; ##merge agg + sort +topk select /*+topk(1 1)*/ c3, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by c3 limit 1; ## with offset select /*+topk(1 1)*/ c3, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by c3 limit 1 offset 4; select /*+topk(1 1)*/ c3, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by c3 limit 1 offset 1000; ##test limit 0 select /*+topk(1 1)*/ c3, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by c3 limit 0; ##complex order by item select /*+topk(1 1)*/ c2, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by avg(c3), sum(c1)/sum(c2) limit 5; select /*+topk(1 1)*/ c1, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by avg(c3) desc, sum(c1)/sum(c2) limit 5; select /*+topk(1 1)*/ c2, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <10 group by c2 order by avg(c3) desc, sum(c1)/sum(c2) + avg(c2) limit 5; ##different topk params select /*+topk(0 0)*/ c2, sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by avg(c3) desc, sum(c1)+sum(c2) limit 5; select /*+topk(50 0)*/ c2, sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by avg(c3) desc, sum(c1)+sum(c2) limit 5; select /*+topk(10000 1)*/ c2, sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by avg(c3) desc, sum(c1)+sum(c2) limit 5; select /*+topk(1 10000)*/ c2, sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk where c2 <12 group by c2 order by avg(c3) desc, sum(c1)+sum(c2) limit 5; ##topk is in subquery select * from (select /*+topk(0 4)*/ avg(c1) from t1_topk where c2 <10 group by c2 order by sum(c2) limit 5) as a; select c1 from t1_topk where c1 < any (select /*+topk(0 4)*/ avg(c1) from t1_topk where c2 <10 group by c2 order by sum(c2) limit 5); select /*+topk(0 4), no_use_px*/ avg(c1) from t1_topk where c2 <10 group by c2 order by sum(c2) limit 5 union (select /*+topk(0 10)*/ sum(c1) from t1_topk where c2 <10 group by c2 order by sum(c2) limit 7); select c1 from t1_topk where (select /*+topk(0 10)*/ avg(c1) from t1_topk where c2 <10 group by c2 order by sum(c2) limit 1) > 1 ; ##TODO:this is not supported ##select (select /*+topk(10 5)*/ avg(c1) from t1_topk where c2 =2 group by a.c2 order by sum(c2) limit 5) from t2_topk as a; #select (select /*+topk(10 5)*/ avg(c1) from t1_topk where c2 =2 group by c2 order by sum(a.c2 + c2) limit 5) from t2_topk as a ; select * from (select /*+topk(10 5)*/ c3, c1, avg(c1), sum(c2), sum(c1) + sum(c2), count(c3), min(c3), max(c1), sum(c2)/count(c1), sum(c3)/sum(c1) from t1_topk group by c2 order by c3 limit 7) as a left join t2_topk on a.c1 = t2_topk.c1 left join t3_topk on t3_topk.c1 = a.c1;